"If another woman is introduced into the situation, then it means the real mother of the child can be questioned," said Mat Jais Kamos from the Islamic affairs department in Malaysia's biggest state, Selangor.
"This creates confusion in Islamic law especially when it comes to inheritance, as it will be hard to determine the individual's bloodline and thus the person's rights to any inheritance," he told AFP.
Mat Jais said a fatwa banning surrogacy was issued by the National Council of Islamic Religious Affairs in 2008. The decision had not been widely reported until now.
"It categorically states that such a form of pregnancy is unacceptable under Islamic law," Mat Jais said, adding that IVF is permissible as long as the sperm and egg belong to a married couple.
"In Islam, it is not permissible for the sperm of the male of a married couple to be implanted into the egg of another woman," he said.
"That is considered a violation because the man is not married to this other woman and yet she is the bearer of his child out of wedlock."
The Straits Times newspaper reported on the weekend that surrogacy is on the rise in Malaysia, but that there were a lack of rules to govern the practice.
"Practitioners, surrogates and couples are not going to talk about it because of the sensitive and emotive nature of the entire procedure," Obstetrical and Gynaecological Society of Malaysia president Mohamad Farouk Abdullah told the daily.
"That is why there are no statistics on surrogacy in Malaysia."
Islam is the official religion of Malaysia, where more than 60 percent of the population of 27 million are Muslim Malays.
Religious authorities have previously caused waves with other bans including one on yoga, which Islamic clerics said could erode faith in Islam because it involved physical and religious elements of Hinduism.
Even when a fatwa is issued, it is up to the religious authorities in each state to decide whether to enforce it.
However, bans on alcohol and sex out of marriage are in some parts of the country enthusiastically enforced by "morality police" who carry out raids on hotels and pubs.